INFO: task hung in tty_release

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syzbot

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Jul 15, 2018, 9:29:07 AM7/15/18
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Hello,

syzbot found the following crash on:

HEAD commit: 3ee15ba60e6b Add linux-next specific files for 20180712
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11b78d62400000
kernel config: https://syzkaller.appspot.com/x/.config?x=fe1c3df2c7c0c81
dashboard link: https://syzkaller.appspot.com/bug?extid=a44f0127b8fa88f2806b
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [gre...@linuxfoundation.org jsl...@suse.com
linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a44f01...@syzkaller.appspotmail.com

FAT-fs (loop5): Invalid FSINFO signature: 0x00000000, 0x00000000 (sector =
1)
Unknown ioctl 4724
Unknown ioctl 4724
INFO: task syz-executor6:4661 blocked for more than 140 seconds.
Not tainted 4.18.0-rc4-next-20180712+ #6
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6 D23840 4661 3578 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2853 [inline]
__schedule+0x87c/0x1ed0 kernel/sched/core.c:3501
schedule+0xfb/0x450 kernel/sched/core.c:3545
schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3603
__mutex_lock_common kernel/locking/mutex.c:1003 [inline]
__mutex_lock+0xbf5/0x1680 kernel/locking/mutex.c:1073
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
tty_lock+0x70/0xa0 drivers/tty/tty_mutex.c:19
tty_release+0x196/0x1300 drivers/tty/tty_io.c:1638
__fput+0x35d/0x930 fs/file_table.c:252
____fput+0x15/0x20 fs/file_table.c:288
task_work_run+0x1ec/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x40fb51
Code: 33 ff ff 83 45 00 01 48 83 c4 38 48 89 d8 5b 5d c3 0f 1f 84 00 00 00
00 00 e8 1b 32 ff ff 83 38 04 74 50 48 8b 7d 08 e8 cd 3b <00> 00 83 f8 02
7e 36 48 8b 7d 08 41 b9 d8 e4 41 00 41 b8 50 e6 41
RSP: 002b:00007ffde1c6bbb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000018 RCX: 000000000040fb51
RDX: fffffffffffffff7 RSI: 0000000000732a28 RDI: 0000000000000017
RBP: 0000000000000013 R08: 00007ffde1c6bb30 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffde1c6c260 R15: 00000000007034c0
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 PID: 899 Comm: khungtaskd Not tainted 4.18.0-rc4-next-20180712+ #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
nmi_cpu_backtrace.cold.3+0x48/0x88 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:144 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:231 [inline]
watchdog+0xb81/0x10f0 kernel/hung_task.c:292
kthread+0x345/0x410 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.174
msecs
NMI backtrace for cpu 1
CPU: 1 PID: 4663 Comm: syz-executor6 Not tainted 4.18.0-rc4-next-20180712+
#6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__lock_acquire+0x20e/0x5020 kernel/locking/lockdep.c:3462
Code: 90 00 00 00 48 8d 79 08 48 c7 01 00 00 00 00 48 83 e7 f8 48 c7 41 4c
00 00 00 00 48 29 f9 83 c1 54 c1 e9 03 f3 48 ab 44 89 f8 <48> 8b b4 24 58
03 00 00 65 48 33 34 25 28 00 00 00 0f 85 03 34 00
RSP: 0018:ffff88019538edd0 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 1ffff10032a71e37 RCX: 0000000000000000
RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffffed0032a71e20
RBP: ffff88019538f160 R08: 0000000000000000 R09: 0000000000000001
R10: 000000000000080f R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff88f928a0 R14: ffff8801945866c0 R15: 0000000000000000
FS: 00007f0ad2819700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32923000 CR3: 00000001ce598000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
rcu_lock_acquire include/linux/rcupdate.h:244 [inline]
rcu_read_lock include/linux/rcupdate.h:629 [inline]
cgroup_account_cputime include/linux/cgroup.h:726 [inline]
update_curr_rt+0x364/0xd60 kernel/sched/rt.c:972
pick_next_task_rt+0x5c7/0x820 kernel/sched/rt.c:1565
pick_next_task kernel/sched/core.c:3360 [inline]
__schedule+0x1401/0x1ed0 kernel/sched/core.c:3475
schedule+0xfb/0x450 kernel/sched/core.c:3545
do_sched_yield+0x18f/0x250 kernel/sched/core.c:4978
yield+0xa5/0xe0 kernel/sched/core.c:5053
tasklet_kill+0x4e/0xd0 kernel/softirq.c:562
ppp_sync_close+0x96/0x110 drivers/net/ppp/ppp_synctty.c:238
ppp_sync_hangup+0x15/0x20 drivers/net/ppp/ppp_synctty.c:254
tty_ldisc_hangup+0x138/0x640 drivers/tty/tty_ldisc.c:717
__tty_hangup.part.21+0x2da/0x6e0 drivers/tty/tty_io.c:621
__tty_hangup drivers/tty/tty_io.c:571 [inline]
tty_vhangup+0x21/0x30 drivers/tty/tty_io.c:694
pty_close+0x3bd/0x510 drivers/tty/pty.c:78
tty_release+0x4b3/0x1300 drivers/tty/tty_io.c:1656
__fput+0x35d/0x930 fs/file_table.c:252
____fput+0x15/0x20 fs/file_table.c:288
task_work_run+0x1ec/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455a79
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0ad2818c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f0ad28196d4 RCX: 0000000000455a79
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000016
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004eb5d2 R14: 00000000004c8d00 R15: 0000000000000000


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syzbot

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Feb 22, 2019, 5:22:11 AM2/22/19
to syzkaller-upst...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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